Rough Idle Once in A While

[spieg16]

Hey guys, i have noticed every once in a while when my explorer is warm and I start it up it will not want to idle smoothly at all. The idle will drop to about 200 RPM and jump back up to about 400 and then drop again, but the car does not stall. Driving it for a little while makes it a bit better, but once you turn the car off it's a 50 50 chance if it does this again when you start it back up, but more times than less it does unless it sits for a few hours until you start it up again. Like i said this only happens every once in a while. Also i noticed that when it turn my heat on my idle drops down and my car runs rougher than normal, I know that turns the AC on but shouldnt the engine compensate for that. I cleaned my IAC and MAF a few weeks ago, but i dont think i was able to clean the IAC very well.

Any help is appreciated, Jason

 

[Turdle]

You might try cleaning the IAC again--pay ayyention to the plunger shaft.

Also, check the vacuum connections to this--

http://www.explorerforum.com/forums/showthread.php?t=169945&highlight=globe

 

[spta97]

When this is happening (rough idle), disconnect the harness to the IAC. If nothing happens (the engine should idle worse) just replace it. It is a $50 part (on the V8 anyway).

I had luck cleaning my MAF, but cleaning my IAC made it even worse. Replacing it on my 2000 AWD was a 3 minute job. I was getting a check engine light though so it was obviously bad.

 

[Eddie V]

Check your fuel pressure, and specifically the fuel pressure regulator. I had a similar problem on a GM car and it was the regulator. Symptoms were only present on a warm start. Cold start no problem. I had to let the car cool down for it to turn on and idle properly.